Field of the Invention
This invention relates to isolation technology and more particularly to providing power across an isolation barrier.
Description of the Related Art
An exemplary low power application (e.g., a system having a power level of approximately 1 W or less) may use a power converter that transfers power across an isolation barrier between systems having different voltage planes, (e.g., a voltage plane of a processor system and a voltage plane of a load system having a large DC or transient voltage difference between the voltage planes). Referring to FIG. 1, a conventional high-power system (e.g., a system having a power level greater than approximately 1 W) uses a power converter including standard transformer 102, e.g., a discrete transformer with a ferrite core and high efficiency to transfer power across the isolation barrier. Depending on the complexity of the drive circuitry, the conventional high power system may achieve power transfer efficiencies of approximately 70%-approximately 95%. Referring to FIG. 2, in order to regulate the output voltage, opto-isolator 204 or other communications technique provides any necessary feedback signals across the isolation barrier. Although the standard transformer implementation is efficient, the size and cost of the standard transformer implementation may be prohibitive for use in some applications. However, some low power applications tolerate lower efficiencies. Thus, low-cost, isolated power transfer systems having reasonable power transfer efficiency (e.g., power transfer efficiency greater than 40%) are desired.